Itinerant antiferromagnetism and its manifestation in the spin dynamics of SrCr<sub>2</sub>As<sub>2</sub>
ORAL
Abstract
Neutron diffraction and magnetic susceptibility studies of polycrystalline SrCr2As2 reveal that this compound is an itinerant G-type antiferromagnet below the Neel temperature TN = 590(5) K with the Cr magnetic moments aligned along the tetragonal c axis. The system remains tetragonal to the lowest measured temperature (~12 K). The ordered moment, μ = 1.9(1) μB/Cr, measured at T = 12 K, is significantly reduced compared to its localized value (4 μB/Cr) due to the itinerant character brought about by hybridization between the Cr 3d and As 4p orbitals. Inelastic neutron scattering measurements on powder samples show steep columns of magnetic scattering arising from the magnetic Γ points, with the magnetic spectra persisting up to at least 150 meV. The spectra are modeled using a phenomenological J1-J2-Jc Heisenberg description with very large nearest- (J1) and next-nearest-neighbor (J2) AFM interactions within the square tetragonal basal plane and weak interlayer interactions (Jc).
*Work at Ames Laboratory was supported by the DOE, BES, Division of Materials Sciences & Engineering, under Contract No. DEAC02-07CH11358. This research used resources at the Missouri Research Reactor, University of Missouri and Oak Ridge National Laboratory.
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Presenters
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Pinaki Das
- Ames Laboratory, Iowa State University
- Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University